Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
920 am EDT Tuesday Jun 30 2015
weak high pressure will crest across the area today before
another low pressure system approaches from the west late today
through Wednesday. The system will bring showers and thunderstorms
to the region on Wednesday before high pressure moves in on
Thursday. High pressure then remains in place into the weekend.
Near term /until 7 PM this evening/...
mostly sunny skies in place across the County Warning Area this morning. With the
exception of the Connecticut River valley near Lebanon...Valley
fog has burned off at most locations. Forecast largely in good
shape but will update for current temperature trends.
650 am...minor estf update to the 1st period grids to reflect
satellite trend and incorporate latest mesonet.
we'll see weak ridging today ahead of the impulse currently
diving southeast into the Great Lakes on GOES water vapor imagery.
Clouds were scattering out over southern sections of the forecast
area as of 06z with approach of the ridge. With our narrow
temperature/dewpoint spread...that should spell some early morning
fog and stratus. Early morning fog and stratus will burn off...and
we'll see several hours of sunshine before the ridge exits the
coast and opens the door for clouds to overspread the area in
advance of the next system. Warm air advection may give rise to a
few showers...isolated thunder vicinity of the Connecticut valley
towards evening...otherwise a dry day anticipated for much of the
region. Highs will be mainly in the 70s with a few 80 degree
readings extreme southern New Hampshire.
Short term /7 PM this evening through 6 PM Wednesday/...
warm air advection clouds and precipitation continues to spread
slowly north and east tonight across the region in the form of
showers and isolated thunder. Lows will range from the middle 50s to
the lower 60s. The warm front will then lift to our north Wednesday
morning...with a second round of showers and thunderstorms ahead
of the cold front Wednesday afternoon and evening. While instability
looks marginal...there should be sufficient shear for a few strong
storms with potential for isolated damaging winds. For now i've
limited enhanced wording to gusty winds given continued
uncertainty. Highs on Wednesday should be in the 70s.
Long term /Wednesday night through Monday/...
upper trough axis and surface cold front will move east Wednesday
night... bringing any lingering shower/thunderstorm activity to an
end. High pressure gradually builds eastward out of the Midwest
and Great Lakes through the weekend. Temperatures generally in the
70s during the day and 50s at night... a little below seasonal
Surface low pressure tracks off the middle Atlantic coast Friday
night and offshore of Cape Cod on Saturday. This feature looks
quite weak and will track far enough south to avoid significant
rain chances for Independence day Saturday. With elongated surface
high pressure axis across the area expect light winds and a sea
breeze to develop. Southern New Hampshire will warm into the upper
70s to near 80 while coastal Maine tops out in the low 70s. Should
be a pretty nice day for all those who may be choosing outdoor
activities to celebrate the 239th anniversary of United States
Amplifying ridge aloft will allow for building warmth over the
area Sunday and Monday with temperatures warming into the 80s for
most of the area by Monday... though an onshore southerly flow
keeps coastal Maine cooler. The next trough will bring rain
chances toward the middle of next week.
Aviation /13z Tuesday through Saturday/...
short term /through 00z Thu/...isolated brief IFR/LIFR possible in
fog through 11z otherwise VFR through 22z. Scattered MVFR after 22z
in showers and isolated thunderstorms. Widespread MVFR expected
on Wednesday in showers and scattered thunderstorms ahead of a
Long term...high pressure builds in behind the cold front
Wednesday night leading to an extended period of VFR conditions.
Cannot rule out nighttime valley fog at Whitefield and Lebanon.
short term /through Wednesday/...quiet today as a weak ridge
traverse the waters. A warm front crosses the area late tonight
and Wednesday morning...followed by a trailing cold front late
Long term...high pressure stretches across the northern United
States and into the Gulf of Maine Wednesday through Saturday. Low
pressure passes southeast of Cape Cod on Saturday but will not
have much of an effect on Gulf of Maine weather. Fairly tranquil
conditions expected through the weekend with fairly light winds
and seas generally less than 3 feet.